Tonks used this spell to help
Harry pack his school trunk when he
was leaving the Dursleys' house.
She said she wasn't very good at housework spells and that her mother used
to be able to even make the socks fold themselves up together.
Tonks' version was a bit messier, but
it certainly got the job done quickly
(OP3).

A Patronus can be commanded by the caster to attack.
Harry controlled his and told it to
attack each Dementor in turn when
they attacked him and Dudley in the
alley near Privet Drive
(OP1). Members of the Order of the Phoenix used their Patronuses to communicate with other Order members (HBP8, DH8, etc.)

A Patronus can also appear as a shapeless silvery mist, but when cast
correctly, it forms a "corporeal Patronus," which means it takes
the form of an actual creature (corporeal means having a physical form, from
"corpus" L. for body).
(OP8)

After a severe emotional upheaval, a witch's or wizard's Patronus may
change form (HBP16);
this happened to Tonks after Sirius' death, when her Patronus
seems to have taken the shape of a wolf
(HBP8).

Lockhart tried this spell on the
escaped Cornish Pixies.
It had no effect. The spell words certainly don't fit the usual format, so
it seems likely that Lockhart
was making the whole thing up on the spot
(CS6).

Petrification

"petrificare" L. to make into stone,
from "petra" L. rock

Not a spell so much as a magical effect, caused by seeing the reflected eyes
of a basilisk.

The Petrification effect resembles death, except that the victim is still
alive, as if in suspended animation. It takes careful examination to discern
whether a victim is in fact Petrified rather than dead. If a
ghost is Petrified, it turns a dark
smoky grey and can only be moved by the use of a fan. The
antidote is made from
mandrake roots
(CS9).

When the spell is cast, the target object glows blue and trembles briefly
before returning to a normal appearance
(OP22,
OP36).

possession

no incantation given

Dark Magical effect of one person's spirit inhabiting
or taking over the body of another.

The only examples of possession are the actions of
Voldemort, the greatest
Dark wizard of the age.

He used this horrible form of intrusion on snakes and small animals while
hiding out in the wilds of
Albania without
a body of his own.

He possessed Quirrell in order to
monitor and control him. In this particular case,
Voldemort's face appeared
protruding from the back of
Quirrell's head
(PS17).

Tom Riddle's memory form, freed
from its diary by life energy from
Ginny Weasley, inhabited the little
girl off and on, forcing her to kill roosters, write on the wall, and so on.
She talked about it later and said that there were long periods of time when
she couldn't remember what had happened to her
(OP23).

Can be cast as a spell, ("Prior Incantato"), in which case
it forces the target wand to emit a ghost image
of the last spell it cast. The images can be dispelled using
Deletrius.

When two wands are forced to duel that have
core material from the same single creature, the result will be
"Priori Incantatem," a display in sequence of the last
spells one of the wands cast. Which
wand will show the spell effect depends on the
willpower of the two wizards involved.

Casting this spell evidently became part of the routine protective
enchantments used on their campsites during the hunt for the
Horcruxes, because escaping from
the Lovegoods' house,
Hermione immediately
began running in a circle around her companions, casting this along with
other protective enchantments before they set up their
tent
(DH22).